Coordinate indicating apparatus and coordinate measurement apparatus for measuring input position of coordinate indicating apparatus

ABSTRACT

A coordinate measurement system including a coordinate indicating apparatus and a coordinate measurement apparatus for determining a position of a contact object including the coordinate indicating apparatus. The coordinate measurement apparatus includes a channel electrode unit including one or more electrodes, wherein capacitance of each of the one or more electrodes or capacitance between the one or more electrodes is changed based on a change in the position of the contact object, and a controller for applying an electrical signal to the channel electrode unit or measuring a reception signal input to the channel electrode unit. The coordinate indicating apparatus includes a conductive tip for forming capacitance with the one or more electrodes of the channel electrode unit, and a resonant circuit unit for generating identification information of the coordinate indicating apparatus, wherein the resonant circuit unit is connected to the conductive tip.

PRIORITY

This application is a continuation application of a prior applicationSer. No. 13/857,713, filed on Apr. 5, 2013, which claimed the benefitunder 35 U.S.C. § 119(a) of a Korean patent application filed on May 11,2012 in the Korean Intellectual Property Office and assigned Ser. No.10-2012-0050371, the entire disclosure of which is hereby incorporatedby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a coordinate indicatingapparatus and a coordinate measurement apparatus for measuring an inputposition of the coordinate indicating apparatus, and more particularly,to a coordinate indicating apparatus such as a finger or a stylus penand a coordinate measurement apparatus for measuring an input positionof the coordinate indicating apparatus.

2. Description of the Related Art

Currently, devices such as a smart phone and tablet PC are activelyunder development with capability for a contact position measurementapparatus embedded therein. Specifically, the smart phone or the tabletPC generally includes a touch screen, and a user designates a particularcoordinate of the touch screen by using a finger or a stylus pen. Theuser inputs a particular signal in the smart phone by designating theparticular coordinate of the touch screen.

The touch screen may recognize input based on electricity, infraredlight, ultrasonic waves and the like. For example, an electricity baseddevice includes a Resistive type touch screen (R type touch screen) or aCapacitive type touch screen (C type touch screen). Among touch screens,the R type touch screen capable of recognizing a user's finger and astylus pen has been widely used, but the R type touch screen isproblematic in that there is screen glare due to an air space betweenIndium Tin Oxide (ITO) layers. More specifically, transmissivity oflight penetrating a display is reduced due to the air space between theITO layers, and external light reflection is increased.

Currently, the C type touch screen is also widely applied. The C typetouch screen operates by detecting a difference in capacitance of atransparent electrode generated by a contact of an object. However, theC type touch screen has difficulty in physically distinguishing betweena hand and a pen, resulting in an unintended operation error by acontact of the hand which may occur when the pen is used.

Software for distinguishing between the hand and the pen according to acontact area and a method including a separate position measurementapparatus such as an Electro Magnetic Resonance (EMR) technique as wellas the C type touch screen has been used to solve the contact problem.However, software does not completely resolve the unintended operationerror generated due to the contact of the hand, and implementing themethod including the separate measurement apparatus increases size,weight, and cost of the device, by requiring additional components.

Therefore, there is a need for a technology capable of performing adetermination without operation error when an object such as the styluspen is used, without using a separate position measurement apparatus.

SUMMARY OF THE INVENTION

Accordingly, an aspect of the present invention is to solve theabove-mentioned problems occurring in the prior art, and to provide atleast the advantages below. According to an aspect of the presentinvention a coordinate indicating apparatus and a coordinate measurementapparatus is provided, which determines input positions of a stylus penand a conductive object while including only a single touch screen.According to a further aspect of the present invention, a coordinateindicating apparatus and a coordinate measurement apparatus is provided,which distinguishes types of contact objects including a stylus pen andother conductive objects, such as a finger.

According to an aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject including the coordinate indicating apparatus is provided. Thecoordinate measurement apparatus includes a channel electrode unitincluding one or more electrodes, wherein capacitance of each of the oneor more electrodes or capacitance between the one or more electrodes ischanged based on a change in the position of the contact object, and acontroller for applying an electrical signal to the channel electrodeunit or measuring a reception signal input to the channel electrodeunit. The coordinate indicating apparatus includes a conductive tip forforming capacitance with the one or more electrodes of the channelelectrode unit, and a resonant circuit unit for generatingidentification information of the coordinate indicating apparatus,wherein the resonant circuit unit is connected to the conductive tip,wherein the controller determines an input position of the contactobject based on a change in the capacitance of each of the one or moreelectrodes or the capacitance between the one or more electrodes, anddistinguishes a type of the contact object based on a frequency responsecharacteristic of the reception signal.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject including the coordinate indicating apparatus is provided. Thecoordinate measurement apparatus includes a channel electrode unitincluding one or more electrodes, wherein capacitance of each of the oneor more electrodes or capacitance between the one or more electrodes ischanged based on a change in the position of the contact object, adriver for applying an electrical driving signal to the channelelectrode unit, a detector for detecting a reception signal of thechannel electrode unit, and a controller for determining the position ofthe contact object and a type of the contact object. The coordinateindicating apparatus includes a resonant circuit for outputtingidentification information of the coordinate indicating apparatus,wherein the controller determines the position of the contact objectbased on the reception signal detected by the detector for a firstperiod in which the driver applies the electrical driving signal anddetermines the type of the contact object based on the reception signaldetected by the detector for a second period in which the driver doesnot apply the electrical driving signal.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject corresponding to at least one of the coordinate indicatingapparatus and a conductive object is provided. The coordinatemeasurement apparatus includes a channel electrode unit including one ormore electrodes, wherein capacitance of each of the one or moreelectrodes or capacitance between the one or more electrodes is changedbased on a change in the position of the coordinate indicatingapparatus, and a controller for applying electrical signals having twoor more different frequencies to the channel electrode unit or measuringa reception signal received by the channel electrode unit. Thecoordinate indicating apparatus includes a resonant circuit foroutputting identification information of the coordinate indicatingapparatus, wherein the controller determines the position of the contactobject from a response characteristic for one frequency and determinesat least one of a type of the contact object and a contact pressure froma response characteristic for the other frequency.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of thecoordinate indicating apparatus is provided. The coordinate measurementapparatus includes a channel electrode unit including one or moreelectrodes, wherein capacitance of each of the one or more electrodes orcapacitance between the one or more electrodes is changed based on achange in the position of the coordinate measurement apparatus, a driverfor applying an electrical signal to the channel electrode unit, areceiver for receiving the electrical signal from the channel electrodeunit, and a controller for determining a contact pressure of thecoordinate measurement apparatus. The coordinate indicating apparatusincludes a conductive tip for exchanging the electrical signal with thedriver, wherein the conductive tip is capacitive-coupled with thechannel electrode unit, and a passive circuit connected to theconductive tip, wherein a response characteristic of the passive circuitis changed according to the contact pressure of the coordinateindicating apparatus, wherein the controller measures the contactpressure of the coordinate measurement apparatus based on responsecharacteristics of the passive circuit detected by a detector in two ormore different sections of an equal period.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject including the coordinate indicating apparatus is provided. Thecoordinate measurement apparatus includes a channel electrode unitincluding one or more electrodes, wherein capacitance of each of the oneor more electrodes or capacitance between the one or more electrodes ischanged based on a change in the position of the contact object, and acontroller for applying an electrical signal to the channel electrodeunit or measuring a reception signal of the channel electrode unit. Thecoordinate indicating apparatus includes a conductive tip for formingcapacitance with the one or more electrodes of the channel electrodeunit, a grounding unit for forming an electrical connection with a userthrough at least one of a direct contact and a capacitive coupling, aresonant circuit unit connected to the conductive tip, and a switch unitfor forming a resonance when a contact pressure of the conductive tip isequal to or higher than a preset threshold, and not forming theresonance when the contact pressure of the conductive tip is lower thanthe preset threshold.

According to another aspect of the present invention, a coordinatemeasurement apparatus for determining a position of a contact objectcorresponding to at least one of a coordinate indicating apparatus and afinger is provided. The coordinate measurement apparatus includes achannel electrode unit including one or more electrodes, whereincapacitance of each of the one or more electrodes or capacitance betweenthe one or more electrodes is changed based on a change in the positionof the contact object, and a controller for measuring reception signalsfrom the coordinate indicating apparatus and the channel electrode unit,and distinguishing a type of the contact object based on a frequencyresponse characteristic of the reception signals.

According to another aspect of the present invention, a coordinateindicating apparatus for inputting an input coordinate into a coordinatemeasurement apparatus having one or more electrodes is provided. Thecoordinate indicating apparatus includes a conductive tip for formingcapacitance with the one or more electrodes, and a resonant circuit unitfor receiving resonance energy from the coordinate measurement apparatusthrough a capacitive coupling, wherein the resonant circuit unit isconnected to the conductive tip.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of thecoordinate indicating apparatus is provided. The coordinate measurementapparatus includes a channel electrode unit including one or moreelectrodes, wherein capacitance of each of the one or more electrodes orcapacitance between the one or more electrodes is changed based on achange in a position of the coordinate measurement apparatus, a driverfor applying an electrical signal to the channel electrode unit, areceiver for receiving the electrical signal from the channel electrodeunit, and a controller for determining a contact pressure of thecoordinate measurement apparatus. The coordinate indicating apparatusincludes a conductive tip for exchanging the electrical signal with thedriver, wherein the conductive tip is capacitive-coupled with thechannel electrode unit, a switch unit, wherein an on/off state of theswitch unit is determined according to whether a contact between thecoordinate indicating apparatus and the coordinate measurement system isperformed, and a passive circuit connected to the conductive tip,wherein a response characteristic of the passive circuit is changedaccording to the state of the switch unit, wherein the controllermeasures the state of the switch unit based on response characteristicsof the passive circuit detected by a detector in two or more differentsections of an equal period.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject corresponding to at least one of the coordinate indicatingapparatus and a finger is provided. The coordinate measurement apparatusincludes a channel electrode unit including one or more electrodes,wherein capacitance of each of the one or more electrodes or capacitancebetween the one or more electrodes is changed based on a change in theposition of the contact object, and a controller for applying anelectrical signal to the channel electrode unit or measuring a receptionsignal of the channel electrode unit. The coordinate indicatingapparatus includes a conductive tip for forming capacitance with the oneor more electrodes, a grounding unit for forming an electricalconnection with a user through at least one of a direct contact and acapacitive coupling, and a resonant circuit disposed between theconductive tip and the grounding unit, the resonant circuit having ahigh-impedance characteristic in a particular resonance frequency,wherein the controller measures response characteristics for resonancefrequencies of two or more electrodes in the channel electrode unit andcalculates the position of the coordinate indicating apparatus fromrelative sizes of the response characteristics.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject including the coordinate indicating apparatus is provided. Thecoordinate measurement apparatus includes a channel electrode unitincluding one or more channel electrodes, a driver for applying anelectrical signal to the channel electrode unit, a receiver forreceiving the electrical signal from the channel electrode unit, and acontroller for determining a contact position of the coordinatemeasurement apparatus. The coordinate indicating apparatus includes aconductive tip for forming capacitance with the one or more channelelectrodes of the channel electrode unit, a passive resonant circuitunit for receiving energy for a resonance through a capacitive couplingbetween the channel electrode of the channel electrode unit and theconductive tip, and a grounding unit for forming an electricalconnection with a user through at least one of a direct contact and thecapacitive coupling.

According to another aspect of the present invention, a coordinatemeasurement system including a coordinate indicating apparatus and acoordinate measurement apparatus for determining a position of a contactobject including the coordinate indicating apparatus is provided. Thecoordinate measurement apparatus includes a channel electrode unitincluding one or more electrodes, wherein capacitance of each of the oneor more electrodes or capacitance between the one or more electrodes ischanged based on a change in the position of the contact object, and adriver for applying an electrical signal to the channel electrode unit,a receiver for receiving the electrical signal from the channelelectrode unit, and a controller for determining a contact position ofthe coordinate measurement apparatus. The coordinate indicatingapparatus includes a conductive tip for forming capacitance with the oneor more electrodes of the channel electrode unit, a passive resonantcircuit unit for receiving energy for a resonance through a capacitivecoupling between the electrode of the channel electrode unit and theconductive tip, and a grounding unit for forming an electricalconnection with a user through at least one of a direct contact and thecapacitive coupling.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of variousembodiments of the present invention will be more apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagram illustrating a coordinate indicating systemaccording to an embodiment of the present invention;

FIG. 2A is a diagram illustrating a coordinate measurement apparatusaccording to an embodiment of the present invention;

FIG. 2B is a diagram illustrating a coordinate measurement systemaccording to an embodiment of the present invention;

FIG. 3A to 3E are diagrams illustrating a coordinate indicatingapparatus according to an embodiment of the present invention;

FIGS. 4A to 4C are diagrams illustrating a coordinate indicatingapparatus identifying process according to an embodiment of the presentinvention;

FIG. 5 is a flowchart illustrating a control method of a coordinatemeasurement system according to another embodiment of the presentinvention;

FIG. 6 is a flowchart illustrating a control method of a coordinatemeasurement system according to yet another embodiment of the presentinvention; and

FIG. 7 is a block diagram illustrating a method of measuring a resonancefrequency change by a writing pressure according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, various embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. In thefollowing description, the same or like elements are designated by thesame or like reference numerals throughout the drawings. Further,detailed description of known functions and configurations is omitted toavoid obscuring the subject matter of the present invention.

According to aspects of the present invention, a coordinate indicatingapparatus and a coordinate measurement apparatus which determines inputpositions of a stylus pen and a conductive object while including only asingle touch screen is provided. Further, a coordinate indicatingapparatus and a coordinate measurement apparatus which distinguisheswhether a type of contact object is a stylus pen or a finger isprovided.

FIG. 1 is a diagram illustrating a coordinate indicating systemaccording to an embodiment of the present invention. As illustrated inFIG. 1, a coordinate measurement apparatus 1, according to an embodimentof the present invention, measures a coordinate of an input position bydetecting an input by a coordinate indicating apparatus 2 or a part of auser's body such as a finger 3.

Although the coordinate measurement apparatus 1 is described as a smartphone or a tablet PC, the type of coordinate measurement apparatus 1 isnot limited thereto. The coordinate measurement apparatus 1 can be anyapparatus including a channel electrode unit, a transmitter, and areceiver for measuring a coordinate, described in more detail below.

The coordinate indicating apparatus 2 is implemented as a stylus pen,and can designate a particular coordinate of the coordinate measurementapparatus 1 by being in contact with the coordinate measurementapparatus 1. The coordinate indicating apparatus 2 has a relativelysmaller contact area than that of the finger 3.

The coordinate measurement apparatus 1 determines whether a touch ismade by the coordinate indicating apparatus 2 such as the stylus pen orthe finger 3. That is, the coordinate measurement apparatus 1distinguishes a type of contact object. Here, the contact objectincludes a conductive object such as the finger and the stylus pen whichis distinguished from the conductive object.

The coordinate measurement apparatus 1 first measures an input positionof the contact object 2 or 3. For example, the coordinate measurementapparatus 1 measures the position of the contact object 2 or 3 accordingto a capacitance change due to a contact of the contact object 2 or 3.The position measurement according to the capacitance change will bedescribed below in more detail. Accordingly, the coordinate measurementapparatus 1 measures both the position of the user's finger 3 and theposition of the coordinate indicating apparatus 2 such as the styluspen.

The coordinate measurement apparatus 1 distinguishes a type of thecontact object 2 or 3 after measuring the input position of the contactobject 2 or 3. When the contact object 2 or 3 is the coordinateindicating apparatus 2, the coordinate measurement apparatus 1 canreceive identification information of the coordinate indicatingapparatus 2 from the coordinate indicating apparatus 2. Morespecifically, the coordinate measurement apparatus 1 transmits apredetermined driving signal (hereinafter, referred to as a “Tx signal”)to the coordinate indicating apparatus 2, and determines the type of thecontact object based on a frequency response characteristic of thecoordinate indicating apparatus 2 according to the Tx signal.

That is, when the coordinate measurement apparatus 1 receives aparticular frequency response signal for the Tx signal, it can bedetermined that the coordinate indicating apparatus 2 touches thecoordinate measurement apparatus 1. Further, when the coordinatemeasurement apparatus 1 does not receive the particular frequencyresponse signal, it can be determined that the finger 3 touches thecoordinate measurement apparatus 1.

Accordingly, the coordinate measurement apparatus 1 can first measurethe input position of the contact object 2 or 3, and then distinguishthe type of the contact object 2 or 3.

FIG. 2A is a diagram illustrating a coordinate measurement apparatusaccording to an embodiment of the present invention.

As illustrated in FIG. 2A, the coordinate measurement apparatus 200includes a panel unit 218 and a controller 220. The panel unit 218includes a channel electrode unit 210 including a plurality ofelectrodes 211 through 216 and a connection electrode line 217 forconnecting the channel electrodes and the controller 220. Alternatively,the coordinate measurement apparatus 200 may further include an imagedisplay means such as a LCD or a CRT screen, a glass film or the like.Further, it is assumed that the coordinate measurement apparatus 200measures an input position of the coordinate indicating apparatus 250such as the stylus pen.

The channel electrode unit 210 includes at least one of receptionelectrodes 211 through 213 and at least one of transmission electrodes214 through 216. Here, the transmission electrodes 214 through 216transmit a predetermined transmission signal (hereinafter, referred toas a “Tx signal”) based on an electrical signal input from thecontroller 220 to an outside.

The controller 220 inputs the electrical signal into the transmissionelectrodes 214 through 216 according to a preset order. For example, thecontroller 220 inputs the electrical signal into the transmissionelectrode 214 for a preset period and stops inputting the electricalsignal after the preset period. After the input of the electrical signalinto the transmission electrode 214 stops, the controller 220 inputs theelectrical signal into the transmission electrode 215 for the sameperiod as the preset period.

Further, the controller 220 stops inputting the electrical signal intothe transmission electrode 215 after the preset period and similarlyinputs the electrical signal into the transmission electrode 216. Thatis, the controller 220 inputs the electrical signal preset according tothe order of the transmission electrode 214, the transmission electrode215, and the transmission electrode 216. The number of transmissionelectrodes 214 through 216 can be a different number. Further, althoughit has been illustrated in FIG. 2A that the transmission electrodes 214through 216 are spaced apart from each other by a predetermineddistance, alternatively, the transmission electrodes 214 through 216 mayoverlap with each other for a more precise determination of the inputposition. Additionally, the design a layout pattern of the transmissionelectrodes 214 through 216, is not limited by the layout pattern in FIG.2A and can be changed in other ways. The transmission electrodes 214through 216 may be implemented by, for example, Indium Tin Oxide (ITO).

The Tx signal output from the transmission electrodes 214 through 216 isreceived by the reception electrodes 211 through 213. Electrodes of thetransmission electrodes 214 through 216 sequentially output theelectrical signal based on a preset order. For example, the controller220 inputs the electrical signal into the transmission electrode 214 fora first period and input the electrical signal into the transmissionelectrode 215 for a second period after the first period ends. Thecontroller 220 inputs the electrical signal into the transmissionelectrode 216 for a third period after the second period ends. Here,temporal lengths of the first, second, and third periods may be thesame. Accordingly, the Tx signal is output from the transmissionelectrode 214 for the first period, the Tx signal is output from thetransmission electrode 215 for the second period, and the Tx signal isoutput from the transmission electrode 216 for the third period.

The controller 220 sequentially receives an Rx signal by the receptionelectrodes 211 through 213 based on a preset order or receives the Rxsignal at the same time. Here, the Rx signal includes a responsecharacteristic for the normal Tx signal of the coordinate indicatingapparatus 250 as well as the signal input from one of the transmissionelectrodes 214 through 216. Here it is assumed that the first periodincludes a 1-1 sub period, a 1-2 sub period, and a 1-3 sub period.Further, it is assumed that the second period includes a 2-1 sub period,a 2-2 sub period, and a 2-3 sub period. In addition, it is assumed thatthe third period includes a 3-1 sub period, a 3-2 sub period, and a 3-3sub period. For example, the controller 220 can receive the Rx signalthrough the reception electrode 211 for the 1-1 sub period. Thecontroller 220 can receive the Rx signal through the reception electrode212 for the 1-2 sub period after the 1-1 sub period ends. The controller220 can receive the Rx signal through the reception electrode 213 forthe 1-3 sub period after the 1-2 sub period ends. The controllerreceiving the Rx signal from the reception electrode may be named adetector.

That is, the Tx signal is output from the transmission electrode 214 forthe first period, and the controller 220 can sequentially receive the Rxsignal through the reception electrodes 211 through 213. Conversely, thecontroller 220 can receive the Rx signal through the receptionelectrodes 211 through 213 at the same time.

When the coordinate indicating apparatus 250 touches a particularcoordinate on the channel electrode unit 210, capacitance of thecorresponding electrode or capacitance between the correspondingelectrode and neighboring electrodes may be changed. An intensity of theRx signal may be changed based on the change in the capacitance, and anx-axis coordinate of the input position of the coordinate indicatingapparatus 250 may be determined based on the change in the intensity ofthe Rx signal. For example, Table 1 shows Rx signal intensity changedata in each reception electrode for the first period according to anembodiment of the present invention.

TABLE 1 1-1 sub 1-2 sub 1-3 sub Period period 211 period 212 period 213Amount of 2 8 3 changes in Rx signal intensity

The process described above may be repeated in the same way during thesecond and third periods. That is, the transmission electrode 215transmits the Tx signal for the second period, and the Rx signal isreceived by the reception electrode 211, the reception electrode 212,and the reception electrode 213 for the 2-1 sub period, the 2-2 subperiod, and the 2-3 sub period, respectively. The transmission electrode216 transmits the Tx signal for the third period, and the Rx signal isreceived by the reception electrode 211, the reception electrode 212,and the reception electrode 213 for the 3-1 sub period, the 3-2 subperiod, and the 3-3 sub period, respectively.

Tables 2 and 3 below show Rx signal intensity change data in thereception electrodes for the second and third periods, respectively.

TABLE 2 2-1 sub 2-2 sub 2-3 sub Period period 211 period 212 period 213Amount of 5 15 6 changes in Rx signal intensity

TABLE 3 3-1 sub 3-2 sub 3-3 sub Period period 211 period 212 period 213Amount of 2 4 1 changes in Rx signal intensity

The controller 220 determines the input position of the coordinateindicating apparatus 250 by summing the data shown in Tables 1 through3. As shown in the data of Tables 1 through 3, the intensity of the Rxsignal received by the reception electrode 212 is identified as mostsignificantly changed. Further, as shown in the data of Tables 1 through3, it may be identified that an amount of changes in the Rx signalintensity for the second period is higher in comparison with those forthe first and third periods. Accordingly, the controller 220 determinesthat an x-axis coordinate corresponding to the reception electrode 212is the x-axis coordinate of the input position of the coordinateindicating apparatus 250. In addition, the controller 220 determines ay-axis coordinate corresponding to the transmission electrode 215corresponding to the second period as a y-axis coordinate of the inputposition of the coordinate indicating apparatus 250. That is, thecontroller 220 determines an intersecting point between the transmissionelectrode 215 and the reception electrode 212 as the input position.Alternatively, the controller 220 can determine the coordinate of theinput position by interpolation or various algorithms based on the dataof Tables 1 through 3.

Accordingly, the controller 220 can first determine the input positionof the coordinate indicating apparatus 250. Thereafter, the controller220 determines whether the object used for the touch is the coordinateindicating apparatus 250 or the finger. The coordinate indicatingapparatus 250 can have a specific response characteristic which can beidentification information of the coordinate indicating apparatus forthe Tx signal generated in the transmission electrodes 214 through 216.In this case, the controller 220 can receive the identificationinformation of the coordinate indicating apparatus from the Rx signalsreceived by the reception electrodes 211 through 213. Accordingly, thecontroller 220 can detect whether there is the identificationinformation of the coordinate indicating apparatus in the Rx signals,and thus determine whether the touch is made by the coordinateindicating apparatus 250.

When the user performs a touch with his/her finger or when the userperforms a touch with the coordinate indicating apparatus, thecontroller 220 determines whether there is a specific responsecharacteristic generated by the coordinate indicating apparatus in theRx signals, so that it can be determined whether the touch is performedby the finger or the coordinate indicating apparatus.

That is, the controller 220 distinguishes the type of the contact objectaccording to whether the identification information of the coordinateindicating apparatus is included in the Rx signal.

Alternatively, the controller 220 can apply signals having two or moredifferent frequencies to the transmission electrodes 214 through 216.The controller 220 determines the position of the contact object from aresponse characteristic of one frequency, and determines the type or acontact pressure of the contact object from a response characteristicfor another frequency.

FIG. 2B is a diagram illustrating a coordinate measurement systemaccording to an embodiment of the present invention. As illustrated inFIG. 2B, the coordinate measurement system includes the receptionelectrodes 211 through 213, the transmission electrodes 214 through 216,and a controller 227, and the controller 227 includes a transmissionelectrode control switch 221, a driver 222, a reception electrodecontrol switch 224, a receiver 225, an MCU 226 and the like.

The driver 222 provides a preset electrical signal to the transmissionelectrodes 214 through 216 through the transmission electrode controlswitch 221.

The transmission electrode control switch 221 provides the electricalsignal from the driver 222 to each of the transmission electrodes 214through 216 based on a preset order. As described with reference to FIG.2A, the transmission electrode control switch 221 can connect, forexample, the transmission electrode 214 to the driver 222 for the firstperiod, the transmission electrode 215 to the driver 222 for the secondperiod, and the transmission electrode 216 to the driver 222 for thethird period. The transmission electrodes 214 through 216 can output theTx signal based on the received electrical signal.

The reception electrode control switch 224 connects the receptionelectrodes 211 through 213 to the receiver 225 based on a preset order.For example, the reception electrode control switch 224 connects thereception electrode 211 to the receiver 225 for the 1-1 sub period, thereception electrode 212 to the receiver 225 for the 1-2 sub period, andthe reception electrode 213 to the receiver 225 for the 1-3 sub period.

Additionally, a plurality of receivers can receive the Rx signal by theplurality of reception electrodes 211 through 213 at the same timewithout the reception electrode control switch.

The MCU 226 determines the input position and the type of the contactobject by analyzing the received Rx signal.

FIG. 3A is a diagram illustrating a coordinate indicating apparatusaccording to an embodiment of the present invention.

As illustrated in FIG. 3A, a coordinate indicating apparatus 300includes a conductive tip 310, a resonant circuit unit 320, and agrounding unit 340. One end of the conductive tip 310 is connected toone end of the resonant circuit unit 320. Further, the other end of theresonant circuit unit 320 may be connected to the grounding unit 340.For example, the coordinate indicating apparatus 300 may be implementedin a pen shape.

The conductive tip 310 forms capacitance 313 with channel electrodes 312included in the coordinate measurement apparatus (not shown). Theconductive tip 310 may be constructed as, for example, a metal tip, andforms the capacitance 313 with at least one of the channel electrodes312 of the coordinate measurement apparatus (not shown). The conductivetip 310 may exist within a nonconductive material, or a part of theconductive tip 310 may be exposed to an outside. Further, the channelelectrode 312 may be constructed as a transparent electrode in a lowerend of a transparent window 311 in order to be applied to the touchscreen.

The resonant circuit unit 320 can resonate with the Tx signal receivedfrom the coordinate measurement apparatus (not shown). The resonantcircuit unit 320 can output a resonance signal due to a resonance evenafter the Tx signal input stops. For example, the resonant circuit unit320 can output a sine waveform signal having a resonance frequency ofthe resonant circuit unit. Here the sine waveform signal having aparticular resonance frequency may be the identification information ofthe coordinate indicating apparatus.

That is, when the sine waveform signal having the particular resonancefrequency is included in the Rx signal, the coordinate measurementapparatus determines that the type of contact object corresponds to thecoordinate indicating apparatus.

Alternatively, the resonance frequency of the resonant circuit unit 320may be changed according to a contact pressure of the conductive tip310. For example, when the user is in contact with the coordinateindicating apparatus, the resonance frequency of the resonance circuitunit 320 may be changed.

Accordingly, the coordinate measurement apparatus determines a writingpressure based on the change in the resonance frequency.

Further, the resonant circuit unit 320 may further include a resistorconnected in parallel. Here, the resistor may be a variable resistor,and a resonance characteristic may be changed according to a change in aresistance value. In addition, the coordinate indicating apparatus mayfurther include a switch unit mechanically controlled by the user. Inthe coordinate measurement apparatus, the resonance characteristic maybe changed according to a state of the switch unit. Accordingly, forexample, the user inputs a write/erase function based on an on/off stateof the switch unit.

FIG. 3B is a cross-sectional diagram illustrating the coordinateindicating apparatus according to an embodiment of the presentinvention.

As illustrated in FIG. 3B, the coordinate indicating apparatus includesthe conductive tip 310, the grounding unit 350, an insulator 380, and apassive circuit unit 370.

The conductive tip 310 forms capacitance with electrodes included in thecoordinate measurement apparatus (not shown). A part of the conductivetip 310 may be exposed to an outside of the coordinate indicatingapparatus as illustrated in FIG. 3B.

Additionally, in order to make the user feel a softer tactile feelingwhen using the coordinate indicating apparatus, the coordinateindicating apparatus may further include the insulator for preventingthe conductive tip 310 from directly being in contact with the outside.

The passive circuit unit 370 is electrically connected to the conductivetip 310. The passive circuit unit 370 can generate the identificationinformation of the coordinate indicating apparatus. That is, the passivecircuit unit 370 can make a physical characteristic of the coordinateindicating apparatus different from that of the finger. In FIG. 3A, theresonant circuit unit has been described as an example of the passivecircuit unit 370.

The insulator 380 electrically insulates the conductive tip 310 from thegrounding unit 350.

The shape of the insulator 380 can vary, as long as the insulator 380serves to insulate the conductive tip 310 from the grounding unit 350.

The grounding unit 350 is connected to the passive circuit unit 370, andcan be electrically connected to the user or the coordinate indicatingapparatus through at least one of a direct contact and a capacitivecoupling.

FIG. 3C is a diagram illustrating a coordinate indicating apparatusaccording to another embodiment of the present invention. As illustratedin FIG. 3C, a coordinate indicating apparatus 360 includes theconductive tip 310, a resonant circuit unit 315, a variable impedanceunit 318, and the grounding unit 340.

The conductive tip 310 forms capacitance with electrodes included in thecoordinate measurement apparatus (not shown). The resonant circuit unit315 may be electrically connected to the conductive tip 310. Theresonant circuit unit 315 can generate the identification information ofthe coordinate indicating apparatus and output the generatedidentification information. That is, the resonant circuit unit 315 canmake a physical characteristic of the coordinate indicating apparatusdifferent from that of the finger. Further, the variable impedance unit318 may be implemented by a set of devices of which impedance may bechanged by at least one of the contact pressure and the contact ornoncontact. As the variable impedance unit 318 provides impedancechanged according to at least one the contact pressure and an on/offstate of the user selection switch, the resonance characteristic can bechanged according to the contact pressure and the on/off state of theuser selection switch. The coordinate measurement apparatus determinesat least one state of the contact pressure of the coordinate indicatingapparatus and the on/off state of the user selection switch based on thechanged resonance characteristic. At this time, a configuration of thevariable impedance unit 318 includes reactance or resistance componentschanged according to the contact pressure or the on/off state of theuser selection switch. The resonant circuit unit 315 may have ahigh-impedance characteristic in a particular resonance frequency.

FIG. 3D is a diagram illustrating the coordinate indicating apparatusaccording to an embodiment of the present invention.

As illustrated in FIG. 3D, the coordinate indicating apparatus includesthe conductive tip 310, a coil unit 311, a capacitor unit 312, a switchunit 313, and a grounding unit 314.

The conductive tip 310 forms capacitance with electrodes included in thecoordinate measurement apparatus (not shown). The coil unit 311 and thecapacitor unit 312 form a parallel resonant circuit. As the coil unit311 and the capacitor unit 312 form the resonant circuit, the coordinateindicating apparatus outputs a resonance signal.

The switch unit 313 may be connected to one end of the coil unit 311 andone end of the capacitor unit 312. The switch unit 313 may be controlledmechanically. The resonance characteristic may be changed based on anon/off state of the switch unit 313. For example, a connection betweenthe conductive tip 310 and the resonant circuit is disconnected when theswitch unit 313 is in the off state, and the conductive tip 310 may beconnected to the resonant circuit when the switch unit 313 is in the onstate. As an embodiment of such a configuration, the switch unit 313forms the resonant circuit when the conductive tip 310 is touched with apressure equal to or higher than a preset threshold, and the switch unit313 may not form the resonant circuit by disconnecting an electricalconnection when the conductive tip 310 is touched with a pressure lowerthan the preset threshold. Only when the coordinate indicating apparatusperforms the touch with the pressure equal to or higher than the presetthreshold, the touch can be recognized as an input, and accordingly, itis possible to effectively reduce the input of the coordinate indicatingapparatus generated by an error.

FIG. 3E is a cross-sectional diagram illustrating the coordinateindicating apparatus according to an embodiment of the presentinvention.

As illustrated in FIG. 3E, the coordinate indicating apparatus includesthe conductive tip 310, the grounding unit 330, the insulator 380, thepassive circuit unit 370, and a switch unit 390.

The coordinate indicating apparatus of FIG. 3E may further include theswitch unit 390 in comparison with the coordinate indicating apparatusof FIG. 3B. The switch unit 390 may be electrically connected betweenthe conductive tip 310 and the passive circuit unit 370. As described inconnection with FIG. 3D, the switch unit 390 may operate the resonantcircuit only when the conductive tip 310 is touched with the pressureequal to or higher than the preset threshold.

FIGS. 4A to 4C are diagrams illustrating a coordinate indicatingapparatus identifying process according to an embodiment of the presentinvention.

As illustrated in FIG. 4A, the transmission electrodes 214 through 216output the Tx signal 201. As illustrated in FIG. 4A, the Tx signal maybe a square wave signal and have a predetermined period T1 and amplitudeA. In FIG. 4A, it is assumed that the coordinate indicating apparatus orthe finger is not located near the coordinate measurement apparatus. TheRx signal 202 may have the same period T1 as that of the Tx signal 201.

In FIG. 4B, it is assumed that the user touches a particular point ofthe electrode by using his/her finger 270. As illustrated in FIG. 4B,the Tx signal 201 may be the square wave signal and have thepredetermined period T1 and amplitude A. When the finger is touched (C)in a different manner from that of when the finger is touched (B)before, a size of amplitude of the Rx signal 203 may be changed. Thatis, the amplitude of the Rx signal 203 may be changed by Δ1 fromamplitude (B) of the Rx signal 202 in FIG. 4A

In FIG. 4C, it is assumed that the user touches a particular point byusing the coordinate indicating apparatus. As illustrated in FIG. 4B,the Tx signal 201 may be the square wave signal and have thepredetermined period T1 and amplitude A. A change in amplitude (C) maybe identified for the Rx signal 204 by a capacitance change of thechannel electrode unit of the coordinate indicating apparatus. That is,the amplitude may be changed by Δ1 from the amplitude B of the Rx signal202 in FIG. 4A. The Rx signal 204 may be identified to include a sinewaveform signal in a rest period of the square wave. That is, the Rxsignal 204 includes the identification information of the coordinateindicating apparatus. The coordinate measurement apparatus determinesthat the contact object is the coordinate indicating apparatus based onthe existence of the identification information of the coordinateindicating apparatus in the rest period of the square wave of the Rxsignal 204. That is, the coordinate measurement apparatus determines theposition of the contact object by the Rx signal during a driving periodin which the driver (not shown) applies a driving signal, and determinethe type of the contact object by the Rx signal during the rest periodin which the driver (not shown) does not apply the driving signal.

The square wave and the sine waveform in FIGS. 4A to 4C are merelyexamples.

As described above, for example, a period for identification informationof the coordinate indicating apparatus included in the Rx signal 204from the coordinate indicating apparatus may be changed since theresonance characteristic is changed according to the writing pressure orthe state of the switch unit. The coordinate indicating apparatusdetects the change in the period of the sine waveform, and thusdetermines the writing pressure of the coordinate indicating apparatusor the state of the switch unit.

FIG. 5 is a flowchart of a control method of a coordinate measurementsystem according to another aspect of the present invention.

Each of the transmission electrodes of the coordinate measurementapparatus transmits the Tx signal based on a preset order in Step S501.The coordinate measurement apparatus can receive the Rx signal includinga response characteristic of the coordinate indicating apparatus in StepS503. The coordinate measurement apparatus determines an input positionof a contact object by analyzing a change in a size of the Rx signalduring a Tx driving period in Step S505, and then distinguish a type ofthe contact object by analyzing a response characteristic of a frequencyof the Rx signal during a Tx rest period in Step S507.

FIG. 6 is a flowchart of a control method of a coordinate measurementsystem according to another embodiment of the present invention.

Each of the transmission electrodes of the coordinate measurementapparatus transmits the Tx signal based on a preset order in Step S601.The coordinate measurement apparatus can receive the Rx signal includinga response characteristic of the coordinate indicating apparatus in StepS603.

When the change in the Rx signal size is equal to or smaller than apreset threshold, for example, Δ1 illustrated in FIG. 4B (“no” in StepS605), the coordinate measurement apparatus determines that there is noinput in Step S607.

When the change in the Rx signal size is larger than the presetthreshold, for example, Δ1 illustrated in FIG. 4B (“yes” in Step S605),the coordinate measurement apparatus determines coordinate of input inStep S609.

The coordinate measurement apparatus determines whether there is an ACwaveform within the Rx signal during the Tx rest period in Step S611.When there is the AC waveform within the Rx signal (“yes” in Step S611),the coordinate measurement apparatus determines that the contact objectis the coordinate indicating apparatus in Step S613. When there is no ACwaveform within the Rx signal (“no” in Step S611), the coordinatemeasurement apparatus determines that the contact object is the fingerin Step S615.

FIG. 7 is a block diagram for describing a method of measuring aresonance frequency change by the writing pressure or the switch on/offstate according to an embodiment of the present invention.

The Rx signal may be amplified by an amplifier 701 by a preset gain. Afirst switch unit 702 can output the amplified Rx signal to anintegration unit 703 for a first period. A second switch unit 704 canoutput the amplified Rx signal to an integration unit 705 for a secondperiod.

The first period and the second period have a temporally overlappingsection, but their entire sections are not the same as each other. Thefirst switch unit 702 and the second switch unit 704 can make an on/offcontrol at a predetermined time based on a driving pulse generation andend in a control circuit unit 706. Further, a rectifier may be furtherintroduced to improve reception signal sensitivity.

The control circuit unit 706 measures frequency response characteristicsin different sections of the first period and the second period. Since aratio of the signal measured in each section may be different accordingto a frequency response characteristic of a coordinate indicatingobject, the control circuit unit 706 determines the contact pressure ofthe coordinate indicating apparatus or the on/off state of the switchunit of the coordinate indicating apparatus according to the ratio ofthe signal measured in each section.

That is, the control circuit unit 706 measures the contact pressure orthe switch on/off state based on response characteristics of a passivecircuit in at least two different sections of the same period.

While the present invention has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made withoutdeparting from the spirit and scope of the present invention as definedby the appended claims.

What is claimed is:
 1. An apparatus comprising: a plurality ofelectrodes; and at least one processor configured to: transmit, throughat least one first electrode of the plurality of electrodes, anelectrical transmission signal generated by providing a current to theat least one first electrode during a first time period, receives,through at least one second electrode of the plurality of electrodes, anelectrical reception signal transmitted from a contact object during asecond time period after the first time period, wherein the electricaltransmission signal is provided to the contact object and wherein anelectromagnetic reception signal comprising a magnetic reception signaland the electrical reception signal is generated based on resonanceoccurred in the contact object by using the electrical transmissionsignal, identify a position of the contact object based on at least oneof the electrical reception signal received through the at least onesecond electrode or a capacitance change in the at least one secondelectrode, the capacitance change being generated based on a contact ofthe contact object to the apparatus, and identify a type of the contactobject based on whether the electrical reception signal is received ornot through the at least one second electrode during the second timeperiod after the first time period, wherein the first time periodproviding the current to the at least one first electrode is notoverlapped with the second time period receiving the electricalreception signal transmitted from the contact object.
 2. The apparatusof claim 1, wherein the contact object comprises one of a coordinateindicating apparatus or a finger of a user.
 3. The apparatus of claim 2,wherein the at least one processor is further configured to determinethe type of the contact object to be the finger of the user when thecapacitance change is detected in the at least one first electrode andthe electrical reception signal is not detected.
 4. The apparatus ofclaim 2, wherein the electrical transmission signal is provided to thecoordinate indicating apparatus through a first capacitance formedbetween the at least one first electrode and the coordinate indicatingapparatus.
 5. The apparatus of claim 4, wherein the coordinateindicating apparatus comprises a conductive pen tip.
 6. The apparatus ofclaim 5, wherein a second capacitance is formed between the at least onesecond electrode and the conductive pen tip.
 7. The apparatus of claim5, wherein the electrical reception signal is provided to the at leastone second electrode through the second capacitance formed between theat least one second electrode and the coordinate indicating apparatus.8. The apparatus of claim 2, wherein the coordinate indicating apparatuscomprises a resonant circuit.
 9. The apparatus of claim 8, wherein theresonant circuit receives the electrical transmission signal andresonance occurs in the resonant circuit by using the electricaltransmission signal.
 10. The apparatus of claim 9, wherein theelectrical reception signal is generated from the resonant circuit. 11.The apparatus of claim 9, wherein the coordinate indicating apparatusfurther comprises a grounding unit, and the resonant circuit comprisesan inductor and a capacitor.
 12. The apparatus of claim 11, wherein oneend of each of the inductor and the capacitor is connected to aconductive pen tip of the coordinate indicating apparatus and anotherend of each of the inductor and the capacitor is connected to thegrounding unit.
 13. The apparatus of claim 12, wherein the resonantcircuit further comprises a resistor, and wherein one end of theresistor is connected to the conductive pen tip and another end of theresistor is connected to the grounding unit.
 14. The apparatus of claim9, wherein the coordinate indicating apparatus further comprises avariable impedance unit connected to the resonant circuit.
 15. Theapparatus of claim 14, wherein an impedance of the variable impedanceunit is changed according to a change of a contact pressure between thecoordinate indicating apparatus and the apparatus.
 16. The apparatus ofclaim 15, wherein a frequency of the electrical reception signalgenerated from the resonant circuit is changed as the impedance of thevariable impedance unit is changed.
 17. The apparatus of claim 16,wherein the at least one processor is further configured to identify thecontact pressure between the coordinate indicating apparatus and theapparatus based on the frequency of the electrical reception signalgenerated from the resonant circuit.
 18. A method for identifying aposition of a contact object at an apparatus, the method comprising:transmitting, through at least one first electrode of a plurality ofelectrodes, an electrical transmission signal by providing a current toat least one first electrode of the apparatus during a first timeperiod; receiving, through at least one second electrode of theplurality of electrodes, an electrical reception signal transmitted froma contact object during a second time period after the first timeperiod, wherein the electrical transmission signal is provided to thecontact object and wherein an electromagnetic reception signalcomprising a magnetic reception signal and the electrical receptionsignal is generated based on resonance occurred in the contact object byusing the electrical transmission signal; identifying the position ofthe contact object based on at least one of the electrical receptionsignal received through the at least one second electrode or acapacitance change in the at least one second electrode; and identifyinga type of the contact object based on whether the electrical receptionsignal is received or not through the at least one second electrodeduring the second time period after the first time period, wherein thecapacitance change is generated based on a contact of the contact objectto the apparatus, and wherein the first time period providing thecurrent to the at least one first electrode is not overlapped with thesecond time period receiving the electrical reception signal transmittedfrom the contact object.
 19. The method of claim 18, wherein the contactobject comprises one of a coordinate indicating apparatus and a fingerof a user.
 20. The method of claim 19, wherein the identifying of thetype of the contact object comprises identifying the type of the contactobject to be the finger of the user when the capacitance change isdetected in the at least one second electrode and the electricalreception signal is not detected.
 21. The method of claim 19, whereinthe electrical transmission signal is provided to the coordinateindicating apparatus through a first capacitance formed between the atleast one first electrode and the coordinate indicating apparatus.